Which of the following would be considered a statistical result that we might call "a gender difference"?

A) The members of one gender outperform all other members of another gender on a task.
B) The mean of one gender greatly outperforms the mean of another gender on a task.
C) The mean of one gender usually outperforms the mean of another gender on a task.
D) all of these

All options describe scenarios where there is a difference in performance between genders, which can be considered a gender difference in a statistical context. Option A describes a scenario where every member of one gender outperforms every member of another, which is a clear gender difference. Option B and C describe differences in average performance between genders, which are also considered statistical gender differences.